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URANIUm mINERALIZATION IN THE mUSCOVITE-rich GRANITES OF THE SHALATIN REGION, SOUTHEASTERN DESERT, EGYPT

Chinese Journal Of Geochemistry 2006年第1期25卷 1-15页

作者： GEHAD m. SALEH NUCLEAR mATERIALS AUTHORITY P.O.BOX: 530 EL MAADI CAIRO EGYPT

The younger granitoids of the Shalatin district in the Southeastern Desert of Egypt, are of biotite and two-mica granite compositions. The geochemistry of rare-earth elements (REE), yttrium, thorium and uranium forms the basis for many important methods to reconstruct igneous petrogenesis. Since the recognition that REE, Y, Th, U-rich accessories may play an important role in controlling the geochemistry of crustal melts, a considerable amount of work has been done in an attempt to understand their effects. However, this effort has been almost exclusively focused on three minerals: zircon, monazite and apatite. Nevertheless, the variety of REE-Th-U-rich accessories in granite rocks are neither limited to these three minerals nor are they always the main REE, Y, Th carriers. The geochemistry of REE, Y, Th and U reflects the behavior of accessories and some key major minerals such as garnet and feldspars, and may therefore give valuable information about the conditions of partial melting, melt segregation and crystallization of granite magmas in different crustal regimes. The geochemistry of U and Th during magmatic differentiation has been studied in many granites from different areas and it has been known that the U and Th contents of granitic rocks generally increase during differentiation, although in some cases they decrease. The Th/U ratio can either increase or decrease, depending on redox conditions, the volatile content or alteration by endogene or supergene solutions. The accessory assemblage of muscovite-rich granites and high-grade rocks is composed of monazite, xenotime, apatite, Th-orthosilicate, secondary U-mineralization and betafite-pyrochlore. REE, Y, Th and U are not suitable for geochemical modeling of granitoids by means of equilibrium-based trace element fractionation equations, but are still useful petrogenetic tools.

关键词：铀矿化作用稀土元素花岗岩沙漠埃及

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The chromite deposits associated with ophiolite complexes, Southeastern Desert, Egypt: Petrological and geochemical characteristics and mineralization

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Chinese Journal Of Geochemistry 2006年第4期25卷 307-317页

作者： Gehad m. Saleh Nuclear materials Authority P.O.Box: 530 El Maadi Cairo Egypt

The podiform chromitites occur in a well-preserved mantle sequence consisting of lherzolite-harzburgite with abundant lenses of olivine dunite. The podiform chromitite deposits are common as small and irregularly shaped masses in the Southeastern Desert (SED) of Egypt. The podiform chromitites exhibit a wide range of compositions from high Cr to high Al varieties. The Cr of chrome spinel ranges from 0.67 to 0.88 in olivine-dunite, quite similar to that of the high-Cr chromitite, whereas it is around 0.62 in lherzolite-harzburgite. Primary hydrous mineral inclusions, amphibole and phlogopite, in chrome spinel have been reported for the first time from the Pan-African Proterozoic podiform chromitites. On the other hand, petrographic and geochemical evidence suggests that podiform chromitites in the SED of Egypt were formed as a result of crystallization of mafic melts, probably of boninitic composition, the boninitic parental magmas were probably produced by a second stage of melting above a subduction zone. Three types of chromite ores can be distinguished within the SED of Egypt: (a) sulphide-poor podiform ores; (b) brecciated ores; and (c) sulphide-rich ores. Two textural types of inclusions in chromite are distinguished: (1) primary silicate inclusions generally have high mg-number (>96), Cr and Ni, and are dominated by pargasitic amphibole, forsterite, diopside, enstatite and Na-phlogopite. A diversity of primary and secondary platinum group minerals (PGm) is described from the chromitites, including alloys, sulphides, sulpharsenides and arsenides of Ru, Os, Ir, Rh, Ni, Cu, Fe and Co; (2) in addition to primary PGm and hydrous silicates, the fluids are of low to moderate salinity, sodium-dominated aqueous solutions with complex gas contents. Variable amounts of water, hydrogen, hydrocarbons, carbon dioxides and nitrogen have been determined in inclusion-rich samples. The chondrite-normalized PGE patterns of lherzolite-harzburgite and olivine-dunite have negative

关键词：铬铁矿沉淀蛇绿岩复合物东南沙漠埃及岩石学

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Rare metal-bearing pegmatites from the Southeastern Desert of Egypt:Geology,geochemical characteristics,and petrogenesis

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Chinese Journal Of Geochemistry 2007年第1期26卷 8-22页

作者： Gehad m.Saleh Nuclear materials Authority P.O.Box:530 El-MaadiCairoEgypt

The pegmatite province of the Southeastern Desert (SED) is part of a pegmatite district that extends from Egypt (extends to 1200 km2). Rare metal pegmatites are divided into (1) unzoned, Sn-mineralized; (2) zoned Li, Nb, Ta and Be-bearing; and (3) pegmatites and pegmatites containing colored, gem-quality tourmaline. The Rb/Sr data reflect a crustal origin for the rare metal pegmatites and indicate that the original SED magma was generated during the peak of regional metamorphism and predates the intrusion of post-tectonic leucogranites. These bodies developed an early border zone consisting of coarse to very coarse muscovite+quartz+alkali feldspar, followed by an intermediate zone of dominant quartz+feldspar+muscovite rock. Garnet, tourmaline, beryl, galena, pyrite, amblygonite, apatite and monazite are rare accessories in both zones. Cassiterite tends to concentrate in replacement zones and along fractures in albite+quartz+muscovite-rich portions. The highest concentrations of cassiterite occur in irregular greisenized zones which consist dominantly of micaceous aggregates of green Li-rich muscovite, quartz, albite and coarse-grained cassiterite. The different metasomatic post-solidification alterations include sodic and potassic metasomatism, greisenization and tourmalinization. Geochemically, the pegmatite-generating granites have a metaluminous composition, showing a differentiation trend from coarse-grained, unfractionated plagioclase-rich granite towards highly fractionated fine- to medium-grained, local albite-rich rock. Economically important ore minerals introduced by volatile-rich, rare metal-bearing fluids, either primarily or during the breakdown of the primary mineral assemblages, are niobium-tantalum oxides, Sn-oxides (cassiterite), Li-silicates (petalite, spodumene, euctyptite, and pollucite), Li-phosphates (amblygonite, montebrasite and lithopilite) and minor REE-minerals (Hf-zircon, monazite, xenotime, thorian, loparite and yttrio-fluorite). The pol

关键词：埃及东南部沙漠稀有金属伟晶岩地质地球化学特征岩石成因

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Isovector pairing and particle-number fluctuation effects on the spectroscopic factors of one-proton stripping and one-neutron pick-up reactions in proton-rich nuclei

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Chinese Physics C 2018年第8期42卷 137-158页

作者： Y.Benbouzid N.H.Allal m.Fellah m.R.Oudih Laboratoire de Physique Theorique-Facultéde Physique-USTHB BP32 El-Alia16111 Bab-Ezzouar-Alger-Algeria

Expressions of the spectroscopic factors（SFs） corresponding to one-particle transfer reactions have been established using a schematic *** expressions have been derived by taking into account the isovector neutron-proton（np） pairing correlations and a particle-number projection in the framework of the generalized SharpBCS（SBCS） *** proposed expressions of the projected wave-functions of odd-mass nuclei have been used for this *** formalism has first been tested using the single-particle energies of the schematic picketfence *** is shown that the np pairing and particle-number fluctuation effects are far from negligible and they depend on the pairing gap parameter *** behavior is not the same when the parent nuclei are even-even or *** dealing with the SFs corresponding to one-proton stripping and one-neutron pick-up reactions in proton-rich nuclei have then been established within the framework of the realistic Woods-Saxon *** is shown that the np pairing effect as well as the particle-number projection effect are important and thus have to be included in future calculations of the SF corresponding to these kinds of reactions.

关键词： neutron-proton pairing particle-number projection spectroscopic factor

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Influence of isovector pairing and particle-number projection effects on spectroscopic factors for one-pair like-particle transfer reactions in proton-rich even-even nuclei

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Chinese Physics C 2018年第4期42卷 171-187页

作者： Y.Benbouzid N.H.Allal m.Fellah m.R.Oudih Laboratoire de Physique Theorique-Faculte de Physique-USTHB BP32 El-Alia16111 Bab-EzzouarAlgerAlgeria

Isovector neutron-proton（np） pairing and particle-number fluctuation effects on the spectroscopic factors（SF） corresponding to one-pair like-particle transfer reactions in proton-rich even-even nuclei are studied. With this aim, expressions of the SF corresponding to two-neutron stripping and two-proton pick-up reactions, which take into account the isovector np pairing effect, are established within the generalized BCS approach, using a schematic definition proposed by Chasman. Expressions of the same SF which strictly conserve the particle number are also established within the Sharp-BCS（SBCS） discrete projection method. In both cases, it is shown that these expressions generalize those obtained when only the pairing between like particles is considered. First, the formalism is tested within the rich.rdson schematic model. Second, it is applied to study even-even proton-rich nuclei using the single-particle energies of a Woods-Saxon mean-field. In both cases, it is shown that the np pairing effect and the particle-number projection effect on the SF values are important, particularly in N =Z nuclei, and must then be taken into account.

关键词： neutron-proton pairing particle-number fluctuations spectroscopic factor

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Petrographic and Geochemicial Characteristics of the Kiziloren Formation (Upper Triassic-Lower Jurassic) in the Akpinar (Konya,Turkey) Area

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Acta Geologica Sinica(English Edition) 2012年第6期86卷 1455-1470页

作者： Ali müjdat ÖZKAN Ayse ELmAS Department of Geological Engineering Selcuk University Graduate School of Natural and Applied Sciences Selcuk University

This paper describes the occurrence of dolomite and the mechanism of dolomitization of the Upper Triassic-Lower Jurassic Klzlloren Formation in the autochthonous Bolkardagl unit of the middle Taurus mountains in south western Turkey. Dolomites were analyzed for geochemical, isotopic and crystallographic variation. Dolomites occur as a replacement of precursor carbonate and cement. The dolomite crystals range from 〈10 to -1000 ltm existing as both replacements and cements. Sr concentrations range between 84 and 156 ppm, and the molar Sr/Ca ratios of dolomitizing fluids are estimated to range between 0.0066 to 0.013 ratios. Dolomites are Ca-rich （with average CaCO3 and mgCO3 equal to 56.43 and 43.57 mol%, respectively） and they are non-stoichiometric, with an average Sr=ll6 ppm, Na=286 ppm, mn=81 ppm, Fe=1329 ppm, and ~lSO and ~lac ranges from -0.6%o to -6.1% Pee Dee Belemnite [PDB], and ＋1.2 to ＋3.9%0 PDB. The North American Shale Composition [NASC]- normalized rare earth element （REE） values of the both limestone and dolomite sample groups show very similar REE patterns characterized by small positive Eu （mean=l.32 and mean=l.42, respectively） and slightly or considerably negative Ce （mean=0.61 and mean=0.72, respectively） anomalies and a clear depletion in all REE species. The Klzlloren Formation dolomites have been formed as early diagenetic from mixing zone fluids at the tidal-subtidal environment and at the late diagenetic from basinal brines at the shallow-deep burial depths.

关键词： dolomite Klzdoren Akplnar peritidal petrography geochemistry

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Impact of increased renewables on natural gas markets in eastern United States

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Journal of modern Power Systems and Clean Energy 2017年第3期5卷 424-438页

作者： Neha NANDAKUmAR Anuradha m.ANNASWAmY Institute for Data Systemsand SocietyMassachusetts Institute of TechnologyCambridgeMAUSA Department of mechanical Engineering Massachusetts Institute of TechnologyCambridgeMAUSA

This paper explores the market structures of natural gas and electricity as well as the interdependence of natural gas prices and bids with increasing reliance on natural gas as the penetration of renewable energy resources increases in order to complement their intermittencies. In particular, the paper will attempt to answer the following two questions: What could the generation mix look like in 2030 with a renewable-rich generation landscape and how could this impact gas prices? How do gasfired generator(GFG) generation volatility, their prices,and their bids for gas change between 2015 and 2030 with increased penetration of renewables? In order to answer these questions, computational models are derived using forecasting and regression analysis tools and an auction model.

关键词： Natural gas markets Gas-fired generators Regression analysis Optimal auction model Volatility Gas prices

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Electron Transport in Ga-rich InxGa1-xN Alloys

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Chinese Physics Letters 2007年第10期24卷 2930-2933页

作者： A. Yildiz S. B. Lisesivdin S. Acar m. Kasap m. Bosi Department of Physics Ahi Evran University Kirsehir Turkey Department of Physics Faculty of Science and Arts University of Gazi Teknikokular 06500 Ankara Turkey CNR-ImEm Institute Area delle Scienze 37/A I-43010 Fontanini Parma Italy

Resistivity and Hall effect measurements on n-type undoped Ga-rich InxGa1-xN （0.06 ≤ x ≤ 0.135） alloys grown by metal-organic vapour phase epitaxy （mOVPE） technique are carried out as a function of temperature （15-350 K）. Within the experimental error, the electron concentration in Inx Ga1-x N alloys is independent of temperature while the resistivity decreases as the temperature increases. Therefore, Inx Ga1-xN （0.06 ≤ x ≤0.135） alloys are considered in the metallic phase near the mort transition. It has been shown that the temperaturedependent metallic conductivity can be well explained by the mort model that takes into account electron-electron interactions and weak localization effects.

关键词： coated conductor buffer layer self-epitaxy CeO2

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Effect of Discharge Voltage on an Ion Sheath Formed at a Grid in a multi-Dipole Discharge Plasma

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Chinese Physics Letters 2008年第3期25卷 1011-1014页

作者： m. K. mishra A. Phukan Centre of Plasma Physics.Tepesia Kamrup-782402 Assam INDIA

It is experimentally demonstrated that a relatively strong ion-rich sheath formed at a fixed negative bias of the grid can be changed to a rather weak ion sheath （sheath potential weakly retards electrons） only by increasing the discharge voltage in the system. At sufficiently high negative grid bias, an increase of discharge voltage enhances the ion collection current at the grid. An explanation is put forward in support of this experimental observation. A slight density enhancement with a fall in plasma electron temperature is also observed with the increasing negative grid bias.

关键词： supernova explosion proto-neutron star shock wave

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magnesium Uptake and Palygorskite Transformation Abilities of Wheat and Oat

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Pedosphere 2012年第6期22卷 834-841页

作者： m.H.SALEHI L.TAHAmTANI Department of Soil Science College of AgricultureShahrekord UniversityShahrekord(Iran)

Weathering of clay minerals is a source of nutrients to plants. Palygorskite is a mg-rich fibrous clay mineral that commonly occurs in the soils and sediments of arid regions. Although many studies have examined the environmental conditions required for the formation and stability of palygorskite, information on the transformation of this mineral in the root zone （or rhizosphere） of agricultural crops is limited. This study explored the possibility of palygorskite transformation in the rhizosphere of wheat and oat and compared the ability of these crops to extract structural mg from palygorskite. The crops were cultivated in pots consisting of a mixture of sand from Hamadan region, Iran and Florida palygorskite, irrigated with distilled water, and treated with either complete or mg-free nutrient solutions. After 100 d, mg uptake by the crops was measured. Clay-sized particles in each pot were also separated from the sand and were analyzed through X-ray diffraction （Xrd）. The X-ray pattern of the particles was compared with that of the pure palygorskite particles （before cultivation）. The results showed that palygorskite could provide sufficient mg for the growth of wheat in the pots supplied with mg-free nutrient solution. In spite of the magnesium uptake by both plants from the palygorskite structure, no detectable peaks indicating the transformation of pmygorskite were recognized by Xrd. A decrease of 1.05 nm in peak intensity was more obvious for the pots containing palygorskite and irrigated with mg-free nutrient solution than for the pots irrigated with complete nutrient solution. Although the decrease in peak intensity was greater for oat than wheat, indicating greater palygorskite weathering by oat, mg uptake by oat was low, as evidenced by the deficiency symptoms observed.

关键词： clay minerals nutrient solution rhizosphere weathering X-ray diffraction

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